This invention relates to the field of geophysical prospecting. More particularly, this invention relates to an apparatus and method for detecting underground minerals such as oil, gas, coal, water, and other resources. As used in this disclosure, the term "underground minerals" is used to designate both inorganic substances, such as water, mercury, and uranium, and organic substances, such as petroleum, gas, and coal.
Gaseous substances associated with subterranean deposits of minerals such as oil, gas and other materials, e. g., water and mercury, are known to migrate upwardly towards the earth's surface. In the past, efforts have been made to sample those gases reaching the earth's surface, analyze the samples collected, and generate qualitative data in order to locate promising deposits. The following U.S. Patents disclose several devices and methods contrived in the past for this purpose:
1,843,879; 2,823,984 PA1 2,112,845; 3,084,553 PA1 2,284,147; 3,239,311 PA1 2,345,219; 3,490,288 PA1 2,736,638; 3,594,583
In spite of the many efforts to collect and generate meaningful data providing a significant correlation between sampled gases and commercially exploitable underground minerals, to date no reliable scheme has been successfully implemented on a commercial scale utilizing this gas sampling technique. The results of a recent effort, for example, reported in the Geological Survey of Canada, Paper 73-1, Part B, entitled, "A Preliminary Evaluation of the Applicability of the Helium Survey Technique to Prospecting for Petroleum", to gather significant data in this field demonstrates that current techniques at best provide only marginally useful information.
It is now known that the concentration in the surface soil of gases whose origins are deep varies greatly with time at any one location. Instantaneous sampling techniques, and sampling techniques utilizing relatively short intervals, therefore do not yield accurate information relating to the concentration of such gases. As a result, exploration activities directed to locating promising underground oil, gas, and other minerals have concentrated on other techniques, such as seismic surveying with acoustic waves, electrical and nuclear well logging, test bore drilling, and the like. While such efforts have yieldeduseful results in the past, the growing scarcity of rich depositsand the increasing expense of conducting such exploratory activities have rendered these techniques relatively undesirable.